Contribution to the Study of Lichenicolous Fungi from Northwest Iberian Peninsula (León and Lugo Provinces)

We have found 117 taxa of lichenicolous fungi in the studied area. In this paper, we describe five taxa: Arthonia boomiana on Nephromopsis chlorophylla, Lawalreea burgaziana on Platismatia glauca, Pronectria scrobiculatae on Lobarina scrobiculata, Trichonectria parmeliellae on Parmeliella testacea and Trichonectria rubefaciens ssp. cryptoramalinae on Ramalina. Furthermore, the next records are interesting chorologically from the Iberian Peninsula: Arthophacopsis parmeliarum, Catillaria lobariicola, Lichenopuccinia poeltii, Myxotrichum bicolor, Nanostictis christiansenii, Niesslia lobariae, Opegrpaha sphaerophoricola, Pronectria fragmospora, Rhymbocarpus aggregatus, R. neglectus, and Tremella cetrariicola.


Introduction
Lichenicolous fungi represent a successful group of organisms that live exclusively on lichens, most commonly as host-specific parasites but also as broad-spectrum pathogens, saprotrophs, and commensals [1].However, we recorded some lichenized fungi and even a Myxomycete (Protista) living on lichens in the study area.These findings are not reflected in the title to ensure brevity.
The studied places are located in the Ancares and Courel mountain ranges, Galicia, and León, in the northwest of Spain.They belong to the European network Natura 2000 protected areas, decree 37/2014, and have an area of 102,634 ha.They have been designated by UNESCO as Biosphere Reserves (http://rerb.oapn.es/,accessed on 26 October 2023).The valleys in these mountains are between hillsides with steep slopes; in Ancares, the maximum altitude is that at Pico Miravalles, of 1969 m, whereas Courel is lower, with a maximum altitude of 1639 m.These two zones host some of the best-preserved Atlantic forests in the NW of the Iberian Peninsula.In Ancares, the forest formations are altimontane and are dominated by Betula pubescens, montane Quercus pyrenaica, oligotrophic Alnus glutinosa, and Salix atrocinerea.In addition to these trees, Courel is also characterized by a combination of Fagus sylvatica and Quercus ilex forests.Both places are characterized by large areas occupied by ancient cultivated Castanea sativa, many of which are in a state of abandonment, but they have a high level of lichen biodiversity [2].
Neither in Galicia nor in these mountains have any studies been previously carried out exclusively on lichenicolous fungi, despite several studies describing lichen biodiversity in which lichenicolous are occasionally recorded [3][4][5][6][7][8].A recent study by van den Boom et al. [9] described a new species of lichenicolous Micarea from Courel.
Etymology: Arthonia boomiana is dedicated to Pieter P.G. van den Boom, a good friend and a very experienced lichenologist who has shared much information and samples with the first author during the recent decades.
It is only known from the type locality that it was living with Tremella coppinsii on thalli of corticolous Nephromopsis chlorophylla.

Arthonia coronata Etayo
We found some excellent populations of this species in the region.Its apothecia grow directly on the thallus of Flavoparmelia caperata on small discolored infections (beige or cream brown) surrounded by a black necrotic area, and they have big ascomata, where hairs can be seen even through a magnifying glass.

Arthonia digitata Hafellner
It was found on the upper parts of squamules of Cladonia digitata, usually forming groups where ascomata sometimes overlap with conidiomata of Milospium lacoizquetae.
Loc. 1, on squamules and podetia of C. digitata growing on wood of Castanea sativa, J. Etayo 33,384 (hb. Etayo) A common species that can be found on different lichens.In the studied area, we found it mostly on the apothecia of Pectenia plumbea.
Sometimes, we found infected thalli most likely with its teleomorph, not described so far.As we did not perform molecular studies, their determination is not conclusive.We did not find them on pink spots like the anamorph, but on yellowish-or brown-colored thalli; perithecia were completely immersed in the thallus.Ascomatal wall is composed of several layers, outer layer formed by polygonal, subspherical or ellipsoid cells with a thin wall, except on the angles, where it is thicker, darker and with extracellular pigment.Pseudoparaphyses are septate, not capitated, 2-3 µm wide, simple to occasionally branched over the asci.Asci bitunicate, cylindrical, apically widened, 8-spored, 100-108 × 9.5-11 µm.Ascospores 1-septate, hyaline when young, brown with a verruculose wall when mature, surrounded by a gelatinous sheath 1-2 µm wide, strongly constricted at the septum, with obtuse to more frequently subacute apices too, 14-17.5 × 7-9 µm (22).
We found this species on blackened parts of main branches of Usnea florida and Usnea sp.Some features of it are ascomata small, immersed or semi-immersed with brown wall, K+ greenish brown; asci without foot, 35-40 × 7-9 µm and ascospores uni-to biseriate, 8-11.5 × 4-5 µm.One of the samples on Usnea sp. had ascospores easily broken at the septum.
We found also a sample growing on Ramalina with a little smaller and not sessile perithecia.Endococcus ramalinarius was known from New Zealand on Ramalina leioidea, and it has wider asci, 29-35 × 9-14 µm, and ascospores, 10-13 × 4-5 µm, slightly larger than those of our specimen on Ramalina.
Endococcus aff.parmeliarum Etayo This species was described growing on Parmelia (and also probably on Usnea) from Chile [16].Our sample on Nephromopsis has brown-greenish ascomata, asci bitunicate, hamathecium present in young material, filaments composed of moniliform cells, soon disappearing.Ascospores are a little longer than in the type, 10.5-11 × 5.5 µm, and with a thick gelatinous sheath of 2-3 µm.
Endococcus rugulosus (Nyl.ex Malbr.)Arnold This species is quite common on Aspicilia in this locality.
Recently combined in Endococcus, this apparently rare species was known to be growing only on species of Lasallia (now synonym of Umbilicaria) from Europe, Canary Islands, and Madeira.In mainland Spain, it was known from Madrid [27] and Cáceres [28].

Epithamnolia xanthoriae (Brackel) Diederich & Suija
Conidiomatal wall with long hyphae of textura porrecta and septate; simple or branched conidiophores are typical of the genus.This species has been recorded on a large number of hosts [29] but never on Usnea.The conidiomata in our sample were growing on circular, black dots.Conidia are straight or curved, 3-5-septate, 50-52 × 2-2.5 µm (when mature).
Species of Hemigrapha growing on Peltigerales were studied by Diederich and Wedin [30].These species have two known asexual stages: one producing macroconidia, previously known from H. asteriscus and H. pseudocyphellariae, and one producing only microconidia, known from H. asteriscus and H. atlantica [30].Since the sizes of the conidiomata and conidia in our specimen are very similar to microconidial anamorph of H. asteriscus, we believe that this species so far only collected on Peltigera species could also colonize Lobaria pulmonaria.Furthermore, the only sample of H. asteriscus known from Europe (Switzerland) in Diederich and Wedin [30] was also only with conidiomata.
Intralichen cf.baccisporus D. Hawksw.& M.S. Cole This species was described by Hawksworth and Cole [31] on the hymenium of Caloplaca trachyphylla in the USA (Nebraska), who noted that it has intermediate characteristics between I. christiansenii and I. lichenicola.Our sample lives in the hymenium of Lecanora chlarotera growing on Castanea sativa, which turns black under infection and has conidia, 2-11 cells, 8.5-16 × 6-8 µm.
Loc. 12, on Lecanora chlarotera growing on Castanea sativa, J. nous cells ampulliform, 4-5 × 4 µm, conidia ellipsoid, hyaline, with obtuse apex, basally a bit truncate, with small oil droplets at the ends, (3.5-)4-4.5(-5)× 1.5-2 µm.Species of Hemigrapha growing on Peltigerales were studied by Diederich and Wedin [30].These species have two known asexual stages: one producing macroconidia, previously known from H. asteriscus and H. pseudocyphellariae, and one producing only microconidia, known from H. asteriscus and H. atlantica [30].Since the sizes of the conidiomata and conidia in our specimen are very similar to microconidial anamorph of H. asteriscus, we believe that this species so far only collected on Peltigera species could also colonize Lobaria pulmonaria.Furthermore, the only sample of H. asteriscus known from Europe (Switzerland) in Diederich and Wedin [30] was also only with conidiomata.
Intralichen cf.baccisporus D. Hawksw.& M.S. Cole This species was described by Hawksworth and Cole [31] on the hymenium of Caloplaca trachyphylla in the USA (Nebraska), who noted that it has intermediate characteristics between I. christiansenii and I. lichenicola.Our sample lives in the hymenium of Lecanora chlarotera growing on Castanea sativa, which turns black under infection and has conidia, 2-11 cells, 8.5-16 × 6-8 µm.
The monotypic genus Lawalreea was described [37] for a fungus with pycnidia that open irregularly at the apex, with green upper wall composed of polyhedral cells, conidiogenous cells ampulliform, enteroblastic, and simple and curved conidia.All these features fit well with our fungus.Lawalreea lecanorae differs from our fungus in the larger conidiomata, 30-100 µm diam., larger conidiogenous cells and conidia, these last being (5-)5.5-6.5(-7.5)× 2-3 µm that are also curved.Furthermore, the host is different: apothecia and, rarely, thallus of Lecanora persimilis.For the moment, we think Lawalreea is the best genus for our fungus.
Etymology: We dedicate this species to Ana Rosa Burgaz on the occasion of her retirement, honoring her important lichenological work during her career and her kindness with her lichenological pupils and friends.
This species is clearly pathogenic as the infected lichen thallus becomes papyraceous and grey greenish.It is only known from the type locality.
No other species of Pronectria or Xenonectriella were recorded growing on the genus Lobarina, so there is no doubt it is a new species.However, we placed in the genus Pronectria with some hesitation due to some coincident features with Xenonectriella, especially the ascus type, large, thickened in upper zone and with uniseriate, widely ellipsoid spores.However, the two main features of this genus that separate it from Pronectria are a darkcolored wall, K+ intense purple or violet and ornamented, finally brownish to golden-brown ascospores.None of these are present in P. scrobiculatae.Ascospores in P. scrobiculatae look like young ascospores of Xenonectriella, which are later ornamented and darken.However, we have observed many of them, and they are always colorless even in overmature spores.
Raesaenenia huuskonenii (Räsänen) D. Hawksw., C. Boluda & H. Lindgr.We report a sample of Bryoria sp. with galls morphologically similar to the sexual morph of this species but only with grouped conidiomata forming a stroma, with upper part greenish and the lower brown, with the same pigments as those in the ascomata of this species.Conidiogenous cells ampulliform to cylindrical, conidia slightly sinuous and fusiform, 6-9 × 2 µm.

Rinodina efflorescens Malme
Corticolous lichen occasionally overgrowing other lichens, especially Parmelia sulcata in the region.It prefers growing on thallus border where its small, sorediate squamules can be seen.In the Iberian Peninsula, it has been noted growing on other lichens [54].

Roselliniella cf. atlantica Matzer & Hafellner
We found similar perithecia to those of this species growing isolated or in small groups on Parmelia saxatilis and Platismatia glauca.Perithecia are firstly immersed, then erumpent and finally sometimes sessile, in the latter case with abundant visible setae.Described in Matzer and Hafellner [55] as parasitic on Xanthoparmelia mougeotii and X. verruculifera from Europe.

Sphaerellothecium parmeliae Diederich & Etayo
We commonly found it in the study area living on two corticolous species of Parmelia, P. saxatilis, P. sulcata and more rarely on the saxicolous species P. omphalodes.
Sphinctrina anglica Nyl.We found it on the thallus of Protoparmelia ochrococca, the same host species as in the finds from the British Isles [15].
Tremella sp.We found some thalli of Melanohalea exasperata with small galls.Inside there are not basidia, but structures that look like conidia.We have another specimen of this species from Moncayo (Zaragoza).
Trichonectria cf.australis Etayo We found two specimens probably belonging to this species as described by Etayo and Sancho [16].They have small, grouped, firstly whitish then brown, cupuliform ascomata 100-120 µm diam.; hairs distributed around the ostiole; ascospores 1-septate, ellipsoid to cylindrical, with obtuse ends, easily broken at the septum, 10-13 × 3-3.5 µm.As the diversity of Trichonectria growing on Usnea is really high, we provisionally refer the examined material to T. cf.australis.
Tremella sp.We found some thalli of Melanohalea exasperata with small galls.Inside there are not basidia, but structures that look like conidia.We have another specimen of this species from Moncayo (Zaragoza).
Trichonectria cf.australis Etayo We found two specimens probably belonging to this species as described by Etayo and Sancho [16].They have small, grouped, firstly whitish then brown, cupuliform ascomata 100-120 µm diam.; hairs distributed around the ostiole; ascospores 1-septate, ellipsoid to cylindrical, with obtuse ends, easily broken at the septum, 10-13 × 3-3.5 µm.As the diversity of Trichonectria growing on Usnea is really high, we provisionally refer the examined material to T. cf.australis.
No currently known species of lichenicolous Trichonectria can be confused with T. parmeliellae.Its orange, globose perithecia covered with thin hairs, ascomatal wall orange, K+ reddish and ascospores broadly ellipsoid are very characteristic.Ascomatal wall is Trichonectria-type but wall thickenings are not so easily visible, so the fungus could be confused with a Nectriopsis.There are two species of Nectriopsis it could be confused with: Nectriopsis lecanodes, which is very common on several large lichens from the Lobarion community: Lobaria, Lobarina, Nephroma, Peltigera, and Ricasolia in nearby Galicia localities.This species has pinkish, large ascomata, 250-350 µm diam., hairs with thin wall, asci truncate at the end and ascospores 4-5 µm wide and spirally ornamented [59].Nectriopsis peruvianus [60] has ascospores similar to those of T. parmeliellae.This species is known from South America growing on Cora glabrata and Coccocarpia sp. and differs from T. parmeliellae in its pinkish to whitish perithecia with hairs of thin wall and verruculose ascospores, similar in shape but smaller, 7-9 × 5.5-7.5 µm.
Etymology: Referring to its growth on Parmeliella testacea, a host with few lichenicolous fungi.
Trichonectria rubefaciens is a common species in Europe, and it has also been recorded in the USA [61], always growing on Parmeliaceae species.According to the review of lichenicolous fungi hosts of this species by Brackel [12], it has been recorded on Evernia, Flavoparmelia, Parmelia, Parmotrema, Platismatia, Pleurosticta, and Punctelia.The above description of this subspecies on Ramalina sp.differs from the protologue only in its smaller